Safe exploitation of developed pillars of a coal seam above fire affected areas – a case study

Abstract

It was an extremely challenging task from the safety standpoint to exploit the developed coal pillars in No. 15 top and bottom seams at the Tata Steel Ltd Sijua Colliery by deep-hole opencast blasting above fire affected areas in No. 13 seam and No. 14 seam and a depillaring panel in No. 10 seam. The danger was that the depillaring operations in No. 10 seam could cause subsidence on the floor of the opencast workings and that the ground vibrations generated due to opencast blasting could destabilize the underground fire areas and cause structural damage to isolation stoppings in No. 13 and 14 seams. The scientific approach proposed by the authors may make it possible to extract the locked-up coal without jeopardizing the safety of the fire affected and depillared panels.